Automatic packaging apparatus



J. A. HAMILTON AUTOMATIC PACKAGING APPARATUS Original Filed Feb. 9, 1966Aug. 18,- 1970 9 Sheets-Sheet 1 INVENTOR J0 Z J1. Ham 51 6-012 ATTORAug. 1970 J. A. HAMILTON AUTOMATIC PACKAGING APPARATUS 9 Sheets-Sheet 2Original Filed Feb. 9, 1966 owl I 1970 J. A. HAMILTON 3,524,298

AUTOMATIC PACKAGING APPARATUS Original Filed Feb. 9, 1966 9 Sheets-Sheet5 [ELM $919M Aug. 18, 1970 J. A. HAMILTON 9 Sheets-Sheet 4.

Original Filed Feb. 9, 1965 Aug. 18, 1970 J. A. HAMILTON AUTOMATICPACKAGING APPARATUS 9 sheets-sheet 5 Original Filed Feb. 9, 1966 Aug.18, N70 J. A. HAMILTON AUTOMATIC PACKAGING APPARATUS 9 Sheets-Sheet 6Original Filed Feb. 9, 1965 I ITZMVWwWmW? w I T o 3, 1970 j J. A.HAMILTON 3,524,298

AUTOMATIC PACKAGING APPARATUS Original Filed Feb. 9, 1966 9 Sheets-Sheet'7 T 9A 10A rq 11A /ZZ /Z{ a 22 v VI/I Aug. 18, 1970 J. A. HAMILTON3,524,298

AUTOMATIC PACKAGING APPARATUS Original Filed Feb. 9, 196 9 Sheets-Sheet8 Aug. 18, 1970 J. A. HAMILTON AUTOMATIC PACKAGING APPARATUS 9Sheets-Sheet 9 Original Filed Feb. 9, 1965 NNN @NN QNN l L b 4, QNN l 6[h m1 llll 3N mww 3w .5 E

United States Patent 0."

3,524,298 AUTOMATIC PACKAGING APPARATUS Joel A. Hamilton, Englewood,N.J., assignor to Mahatfy and Harder Engineering Company, Totowa, NJ.Continuation of application Ser. No. 526,081, Feb. 9, 1966. Thisapplication July 1, 1969, Ser. No. 840,131 Int. Cl. B65b 31/04, 47/10U.S. CI. 53-22 46 Claims ABSTRACT OF THE DISCLOSURE An automaticpackaging machine for making hermet ically sealed and evacuated packagesfrom two continuous webs of flexible plastic packaging material, themachine comprising a pair of side-by-side chains driven intermittentlyaround a closed path having upper and lower reaches, there being mountedon the chains a series of spaced clips adapted to grip the side edges ofthe packaging material to carry it along said path past a series ofoperating stations, one of said stations including vacuum forming meansto draw one web into a series of cups, another operating station havinga sealing die arranged to receive filled cups and to seal the marginsthereof to the second web of packaging material, the sealing die alsoincluding evacuating means for withdrawing air from the sealed packagethrough a slit which is closed olf after evacuation has been completed.

This application is a continuation of my copending application Ser. No.526,081, filed Feb. 9, 1966, now abandoned. The invention relates topackaging apparatus. More particularly, this invention relates to suchapparatus which is automatically operable to form evacuated packages, egfrom roll stock of flexible film.

Various machines for making packages automatically have been proposed,and some have proven successful commercially, for example the machinedescribed in US. Pat. 3,125,839. Such machines have been especiallysuited for applications where there are long packaging runs of the sameor similar type of product. However, there are a number of otherpotential applications where it is de sired to package a variety ofdiiferent types of products, or products of different sizes. Themachines available heretofore have not been adequately adaptable forsuch use, primarily because of the effect and time required to alter themachine for making packages of different size, and also because of therelatively high cost of the machines.

Accordingly, it is a general object of this invention to providepackaging apparatus, methods and techniques which are superior to thoseavailable heretofore. A more specific object is to provide automaticpackage-forming apparatus especially adapted to make packages ofdifferent sizes without requiring extensive change-over alternations.Still another object of this invention is to provide such apparatuswhich is economical to construct and operate. Other objects, aspects andadvantages of the invention will in part be pointed out in, and in partapparent from, the following description, considered together with theaccompanying drawings, in which:

FIG. 1 is a perspective view of a complete packaging machineincorporating the present invention;

FIG. 2 is a vertical longitudinal section of FIG. 1 to show theinterrelationship of the main operating elements of the machine;

FIG. 3 is a cross-section taken along line 33 of FIG. 2, providing anend view of the forming station;

FIG. 4 is a detail section showing the clip arrangement for gripping thefilm;

FIG. 5 is a plan view of the clips shown in FIG. 4;

3,524,298 Patented Aug. 18, 1970 FIG. 6 is an enlarged view based on aportion of FIG. 2, to show the clips as they move around the sprocket;

FIG. 7 is a vertical section taken along line 77 of FIG. 3 to show theinternal construction of the heating and forming elements;

FIG. 8 is a vertical longitudinal section showing the internalarrangement at the package finishing station;

FIGS. 9, 10 and 11 are successive plan views of one package cup showingthe sealing sequence;

FIGS. 9A, 10A and 11A are detail sections showing the respective sealingelements in the positions corresponding to the sealing operations ofFIGS. 9, l0 and 11;

FIG. 12 is a perspective View of the sealing die;

FIG. 13 is a perspective view of the base for the sealing die of FIG.12, arranged as an exploded view with FIG. 12 to show theinterrelationship of these two parts;

FIG. 14 is a plan view of the machine, particularly showing theadjustable frame supports and omitting certain other details;

FIG. 15 is a detail elevation taken at line 1515 of FIG. 2 and showingcertain aspects of the longitudinal adjustment mechanism;

FIG. 16 is a detail vertical section taken along line 1616 of FIG. 15;and

FIG. 17 is a detail horizontal section showing further aspects of thelongitudinal adjustment mechanism.

Referring to FIGS. 1 and 2, the machine comprises an outer housing 20within which are mounted two sets of rotatable sprockets 22 and 24adapted to receive a pair of endless side-by-side chains 26 (see alsoFIG. 3) for movement around parallel paths. The left-hand sprockets 22are rotated by a conventional electric motor drive (not shown) includinga four-station Geneva gear to effect an intermittent indexing movementof the chains. Beneath the chains is a roll 28 of flexible plasticpackaging film 30 to be formed by the machine into cup-like receptaclesor pockets (referred to hereinafter as cups).

This film 30 is fed through powered draw-rolls 32 and a slack take-updancer 34 to the lower horizontal reaches of the chains 26. Referringalso to FIGS. 3, 4, and 5, these chains are positioned withinconventional guides 27 and carry a series of film-holding elementscomprising spring-loaded clips 36. These clips are adapted to grip theside edge portions of the film, as it leaves the top roll 35, and tocarry this film around the path defined by the chains.

Each of the clips 36 includes an upper member formed as two side-by-sidefingers 38 riveted solidly to the respective chain 26, and cooperatinglower fingers 40 each pivotally secured to an upper finger at circularsections intermediate the ends. The inboard tip of the lower fingernormally is pressed up against the adjacent tip of its upper finger by atwo-section torsion spring 42 coiled around the pivot axis. The straightends 44 of this spring engage the upper finger while an axial centerelement joining the two spring sections is looped around an car 41 ofthe lower finger. Thus the spring serves to apply the pressure forgripping the film, and also secures the lower finger to its upperfinger.

At the place where the film 30 is to enter the clips 36, two rotatablediscs 46 are positioned adjacent the two chains 28 respectively. Thesediscs engage an outboard tab 48 of the lower fingers 40 of the clips 36as these clips are shifted along the lower horizontal reaches of thechains. The indexing movement of the chains causes this tab to ride upto the top of the disc while the disc rotates. A back-up plate 47 isprovided to prevent upward movement of the upper finger 38.

The indexing movement of the chains 26 carries the film 30 first to aforming station 50 on the lower horizontal reaches of the closed path ofthe chains. This station basically comprises two operating members 52and 54 disposed above and below the film respectively. The upper member52 is bolted to a cross-arm 56 which extends out through the mainmachine frames 58 where it is connected to a pair of longitudinal arms59 pivotally mounted at 60 on respective longitudinal support bars 61.Pivotal movement of arms 59 produces a motion of member 52 basically ina vertical direction. The lower member 54 similarly is secured to across-arm 62 supported by two longitudinal arms 64 each pivoted at 66 onbar 61, thereby to produce basically vertical motion of member 54.

These two forming station members 52 and 54 are reciprocatedsynchronously in opposite directions by respective rods 68 and 70connected to a rocker 72 which is actuated by a cam (not shown) rotatedby the main machine drive motor. By these means, members 52 and 54 aremoved towards and away from the film together, and the motion is timedso that the members engage the film while it is stopped during the dwellperiods between indexing movements, in order to efiect certainpackage-forming operations to be described hereinbelow.

Referring now to FIG. 7, the upper forming station member 52 is a singleunit comprising a heating plate 74 alongside of a vacuum-forming die 76The lower member 54 also is a single unit, and comprises integralsections 78 and '80 arranged to cooperate with heating plate 74 and die76 respectively to assure that the film is held in place properly duringthe heating and forming operations.

The heating plate 74 includes electrical heating rods 82 and is held byan overhead support 84 arranged in conventional manner to provideself-aligning action when plate 74 engages its cooperating section 78 oflower member 54, thereby to assure that the film 30 is pressedreasonably tightly against the rubber sealing edge 75 around the plate.After sealing has been effected, air is withdrawn from above the heatingplate by a vacuum line 88, so as to draw the film lightly up against theplate. Heat thus is transferred to the film so as to soften the plasticmaterial for the subsequent forming operation.

When the two forming station members 52 and 54 move apart, the heatedportion 30a of film is indexed to the next position where this portionis engaged by vacuum-forming die 76 and its cooperating lower section 80during the subsequent dwell period. This forming die comprises fourvertical walls 90, and a conventional diefiller block 92 if desired,defining a die cavity having the shape of the package to be produced.When the upper member 52 has been moved down to operating position, thelower edges of the die walls are arranged to press lightly against thefilm so as to eifect a moderate seal therewith.

With the forming die 76 in operating position, air is withdrawn from thedie cavity by a vacuum line 94 controlled by a vacuum valve (not shown).This valve is operated in synchronism with the chain indexing movement.Evacuation of the die cavity sucks the film up against the die to effecta tight seal therewith, and thereafter causes the film to be stretchedup into the die by atmospheric pressure, so as to form a cup 100suitable to receive the product to be packaged. The depth of the cup iscontrolled by the die-filler 92 secured to the top of the die, whereasthe lateral dimensions are determined by the length and width of thedie.

The cup 100 is formed with fiat marginal portions 104 extending aroundthe cup mouth and in the plane of the mouth. The heat previously appliedto the film portion 30a by plate 74 tends to soften the plastic in aknown manner to accommodate the desired stretching of the film inboardof the margins 104.

The forming die 76 carries at its forward end a slitting knife 108 (seealso FIG. 3) surrounded by a springloaded pressure bar 110 normallyextending down around i the knife blade when the two members 52 and 54are separated. When these members move together towards operatingposition, the right-hand edge of the lower section forces bar up toproduce a high pressure grip on the film between these two parts. Thispressure serves to hold the film in place while the knife 108 makes aslit 112 in the trailing margin of the preceding cup for the subsequentevacuation of the completed package as will be described. This pressuregrip on the film margin also prevents the preceding cup from being drawnback into die 76 when this die is evacuated, and this desired result isaided by providing the lower member with a rubber pad 114 which pressesagainst the film. The vacuum remains on in thedie 76 substantially untilthe end of the dwell period. This assures maximum cooling of thepreviously heated portion 30a and thereby minimizes spring-back of thestretched plastic.

The cups 100 are indexed along to the right (FIG. 2) and move aroundwith sprockets 24 up to the top horizontal reaches of the chains 26. Itmay particularly be noted that the clips 36 are attached to the chain atsuch a distance from the chain centerline that the gap between adjacentclips is essentially unchanged as the clips go around the sprocket. Thisprevents tearing or distortion of the film.

Further indexing movement of the cups 100 carries them beneath a loadingconveyor 116 from which products, such as stacks of luncheon meat 118,are placed in the cups. Thereafter the cups move beneath a roll 120which applies a second web of plastic packaging film 122 over the cups.From there the cups move with top web 122 to a package finishing stationgenerally indicated at 124 and including a second pair of oppositelyreciprocable members 126 and 128. At this station, the loaded cups aresealed to the top web 122 to make complete packages. These packages thenare evacuated and hermetically sealed, separated from one another intoindividual packages, and dropped onto a chute 130 on which they slideout of the machine.

The lower finishing station member 126 is carried by a cross-arm 117supported by a pair of longitudinal arms 132 pivotally connected attheir remote ends 134 to the main machine frames 58. The upper finishingstation member 128 similarly is carried by a pair of arms 136 pivotallyconnected at their remote ends 138 to the main machine frames. Verticalrods 140 and 142 are connected to members 126 and 128 respectively, andextend downwardly to a conventional operating mechanism (not shown)arranged to reciprocate these rods in opposite vertical directions insynchronism with the indexing movement of the cups 100. Thus members 126and 128 are moved towards each other to engage the plastic films 30 and122 when the cups are stopped between indexing movements, and move awaywhen the package finishing operations have been completed.

Referring also to FIG. '8, the lower finishing station member 126includes a base 144 and a sealing die 146 comprising four vertical wallsand a floor (e.g. a conventional die-filler block 147) defining a cavity148 to receive the loaded cup 100. This cavity is the same size as theforming die 76, so that the cup fits snugly in the sealing die. Theupper finishing station member 128 comprises a sealing clamp 150arranged to press down against the die 146 to create an air-tightcompartment and efii'ect a sealing around the mouth of the cup 100A thenin the die.

Extending up into the sealing die cavity 148, just forward -(to theleft, in the drawings) of the rear die wall 152, is an actuator supportplate 153 integral with the base 144 and shaped to conform with theinterior outline of the die cavity. Support plate 153 is formed with avertical evacuation passageway 154 through which extends an elongatehollow gas stud 156, also fixed to the base 144. The top of this gasstud engages the trailing margin 104T of cup 100A, slightly outboard ofthe evacuation slit 112,

and holds this outboard margin approximately up against the top web 122.

At the lower end of passageway 154 there is a vacuum valve 158 which isopened (as by a cam-operated link controlled by the main machine drive)at the start of the dwell period to withdraw air from the interior ofthe cup 100A through slit *112, the air passing around a fluted studsupport 160 in passageway 154. Other passages 162 connect the vacuumdirectly to the die cavity 148 under the plastic film, to assure thatthe pressure on the outside of the cup 100A is equalized with thatinside the cup. Similarly the spaces 164 within the top clamp 150 areconnected to the vacuum passageway 154 by a conduit 166 to maintainequal pressure on both sides of the top web 122. It may be noted that,during evacuation, the cup marginal portion '4T inboard of the slit 112(i.e. towards the center of the cup) is drawn down slightly by theoutflow of air so as to produce a somewhat enlarged evacuation openingand assure reasonably rapid evacuation.

While evacuation of cup 100A is proceeding, a serrated knife 168 in theforward wall 170 of the die 146 is shifted up to cut through both websof plastic film, throughout the full width thereof, to free the nextpreceding package 100'P for removal when the finishing station members126 and 128 subsequently move apart. This knife can be actuated by anyconventional means, e.g. by overtravel of the cam-operated link used toopen the vacuum valve 158. Reverting to FIG. 5, clips 36 are pro videdwith uniformly spaced slots 37 into which the cutting knife passes,thereby permitting the Webs to be cut Without striking the clips. Thespacing of these slots longitudinally is precisely proportioned to theamount of indexing movement of the clips, so as to assure that the knifealways will pass into a slot and not Strike one of the clips.

Simultaneously with evacuation of cup 100A, a permanent seal is madebetween this cup and the top web 122 completely around the mouth of thecup. For this purpose, the top clamp 150' is provided with conventionalheater rods 172 adapted to raise the temperature of the clamp surfacesto a level suitable for producing a permanent seal between the twoplastic films. FIG. 9 shows the permanent seal line 174 extending aroundthe entire periphery of the mouth of cup 100A. The rear (righthand inthe drawings) transverse section of this seal line extends along theleading margin 104L of the following cup 100F. In other words, the sealeffected by the die 146 and the heated clamp 150 extends not only aroundthe cup 100A then being operated on, but also encompasses a part of thefollowing cup IMF in the next position to the rear.

After the evacuation has been completed, the vacuum valve 158 is closedand a permanent seal is made around the evacuation slit 112. This sealis effected by a movable pressure bar 176 (FIG. 8) advantageouslylocated within the sealing die 146. This bar surrounds the gas stud 156and is mounted on actuator rods 177 (FIG. 10A) for sliding movement upto force the plastic film material against a recessed section 178 of theheated clamp 150. FIG. 10 shows the resulting oval seal 180 whichsurrounds the slit 112 in the trailing margin 104T of the cup 100A. Itmay particularly be noted that the movable bar 176 does not requireheating elements because the sealing heat is provided by the clamp 150,thus simplifying the construction. Also, by locating the bar 176intermediate the sides of the die (preferably on the machinecenter-line, as in this embodiment) and making the evacuation slit 112correspondingly, problems of interference at the sides of the packageare eliminated.

The pressure bar actuator rods 177 extend up through the actuatorsupport plate 153 on both sides of the gas stud 156. These rods arereciprocated vertically in synchronism with the machine cycling, forexample by any conventional means such as a cam-controlled link operatedby the main machine motor. After the evacuation seal 180 has thus beencompleted, the vacuum passage 154 is vented to atmosphere through theusual vent valve (not shown) operated, for example, by overtravel of thecam-operated link used to actuate the pressure bar 176. Thereafter, thepressure bar is moved back down to its normal position.

In some applications, it may be desired to inject a small amount ofinert gas into the package. In this case, before the pressure bar 176 israised, the predetermined amount of gas is forced into the gas stud 156by the usual gas line (not shown) at the lower end of the stud. This gasis emitted from the top of the stud through a lateral port 182 whichdirects the gas into the evacuation slit 112. Thereafter the evacuationslit will be closed off by the pressure bar 176 as previously described.

When the die 146 and clamp 150 separate at the end of the sealingoperation, the completely evacuated and sealed package A is indexed tothe next position (to the left (in the drawings). As shown in FIG. 11,when the die and clamp are reengaged, a further transverse seal line 184is placed across the trailing margin 104T of this package 100A, justinboard of the evacuation slit 112 and overlapping the slit seal 180.Thus, when the knife 168 separates the two packages 100A and 100F (thelatter now being in the sealing die), there will be no loss of vacuum.

Reverting to FIG. 10, it may be noted that the forward (left-hand)transverse section 174' of the seal line of the cup in the die cavityfalls exactly on top of the transverse heat-seal line previously made bythe rear edge 186 (FIG. 9A) of the clamp during the preceding cycle.Thus, when using this dimensional relationship, it may not be essentialto provide heat sealing along that forward transverse seal line 174 andfor some applica tions the corresponding sealing surface 188 (FIG. 11A)may be omitted while retaining the next adjacent seal surface 189. Animportant aspect, however, is that the clamp makes a permanent seal inany part of the peripheral seal line 174 where such permanent seal doesnot already exist when the cup is indexed into evacuating position.

Wherever a permanent seal line is to be made, the sealing surfaces ofthe die 146 (i.e. the top edges of the die walls) are provided with aresilient beading 149 of known composition, such as rubber, adapted topress the plastic film up against the mating sealing surfaces of theclamp 150. A layer of such material also is placed on the top of thepressure bar 178 for the same purpose.

One of the special features of the disclosed machine is its adaptabilityto making changes in package size. Generally, any change in length orwidth of the package requires substitution of new forming and sealingdies sized in correspondence to the new package size. This modificationcan readily be effected in a simple manner as a result of the novelmachine design disclosed herein. This design has been based on theprinciple of reducing the number of packaging stations where operationsmust be performed on the film, thereby to minimize the number ofelements which must be repositioned (longitudinally) when the length ofthe package is altered.

In this regard, the forming operations at station 50 are effected by twoopposed mating members 52 and 54 which can readily 'be replaced withcorresponding members of a different size. Moreover, these two membersare arranged to be moved as a unit longitudinally to accommodate thechange in package repeat dimension which occurs when the length of thepackage is altered. The package finishing operations at station 124similarly are carried out by two opposed mating members 126 and 128which are so arranged that they perform the bulk of the evacuating andsealing operations at a single package position. That is, at that singleposition the package is provided with a permanent seal around its entireperipheral seal line, evacuated, and then permanently sealed at theevacuation opening. The finishing station die and clamp which performthese functions are unitary, integral parts which can quickly be removedand replaced by similar units of different size.

Referring to FIGS. 12 and 13, the sealing die 146 may be removed fromits base 144 simply by disengaging the hold-down bolts 190 and liftingthe die up. Essentially, only the walls and floor defining the cavity148 are removed, and the evacuation elements including the gas stud 156with its associated operating parts remain as an integral portion of thebase for use with a new die of the desired size. The base is providedwith a gasket 145 to assure an air-tight seal when bolted together withany size die 146. Also, the base carries pivoted side arms 169 adaptedto be pushed up to engage a knife actuator 168a to operate the knife168, regardless of the distance between that knife and the rear(right-hand) edge of the sealing die then installed on the base.

Thus the die 146 is removable and replaceable in its entirety withoutthe need for making dimensional adjustments between multiple parts. Allof the peripheral sealing surfaces 190-198 are part of a single module,formed as a single casting, and only that module is replaced to providean entirely new set of sealing surfaces. The mating top clamp 150similarly is replaced as a unit merely by unbolting it from its supportand substituting a new one matching the new die.

If the width of the package is changed, it is necessary to change thelateral spacing of the film clips 36 carried by the chains 26. Referringnow to FIG. 14, this is accomplished by a crank 200 which directlyrotates a first threaded shaft 202, and indirectly rotates a secondthreaded shaft 204 through the intermediary of a gear-chain connection206. Screwed onto shafts 202 and 204 are hubs 208 carrying spacedvertical walls 210 to which the chain guides 27 (see FIG. 3) areattached. Thus, as the crank 200 is turned, the walls 210 move in or outto alter the spacing between the clips 36, as required for the new filmwidth.

The movable walls 210 also include means for rotatably supporting thesprockets 22 and 24 for the chains 26. At the left-hand end of themachine, sprockets 22 are mounted on a splined shaft 212 which isrotated by a drive mechanism 214 connected to the main machine motor(not shown). To effect movement laterally of these sprockets 22 on thesplined shaft, the walls 210 are provided with yokes 216 adapted toengage the opposite sides of the sprockets. The movable walls 210 alsoare secured to respective horizontal cover plates 211 (see FIG. 1) whichare positioned out over the chains 26 and are shiftable with the Walls210, back and forth under the horizontal surface of the main housing 20.

When the length of the package (i.e. the repeat dimension) is changed,it ordinarily will be necessary to change the longitudinal positioningof the forming die 76, in order to provide a whole number of packagerepeats between the edge of the forming die and the corresponding edgeof the sealing die 146. Referring now to FIGS. 15l7, this adjustment ismade by a mechanism arranged to move longitudinally the support bars 61(see also FIG. 2) to which the forming station arms 59 and 64 arepivoted at 60 and 66 respectively, thereby moving the entire formingstation 50 to any desired new position. This adjustment mechanismincludes a rack 220 for each plate 61, and a pinion 222 engaged witheach rack. These pinions are mounted on a shaft 224 carrying anotherpinion 226 engaged with a worm 228 which is rotatable by a knob 230.Thus when the knob is rotated, both plates 61 are moved correspondinglyto adjust the longitudinal distance between the forming station 50 andthe finishing station 124.

A change of the package repeat dimension also requires a change in theamount of indexing movement produced each cycle, i.e. a change in theeffective gear ratio of the machine drive train. In the presentembodiment,

this change is accomplished by altering the number of teeth on theGeneva sprocket, in incremental steps of two teeth at a time. Thearrangement is such that for each two teeth added to this sprocket, thelongitudinal movement of the clips 36 during indexing is increased by/8". Since as explained hereinabove the slots 3'7 of the clips 36 areuniformly spaced at intervals, the incremental change in indexingmovement of /8" (or multiples thereof) will maintain the alignmentbetween these slots 37 and the cutting knife 168; that is, the knifewill always enter the slots and not strike the clips.

Another important feature of the disclosed machine is its compactconfiguration. In one aspect thereof, the overall length is minimized byproviding the forming station 50 at the lower horizontal reaches of thechain movement, so that the length of the upper horizontal reaches neednot be so great as to accommodate both the forming and finishingstations. This lower placement of the forming station requires that thefilm 30 be conducted around the curved path of the sprockets, but asnoted hereinabove the problems of film tearing or distortion whiletraversing that curved path have been solved by using a specialdimensional relationship between the clips 36 and the chain center-linewhich maintains virtually constant the gap between adjacent clips. Theconstruction of the machine also has been simplified by placing the rollof top film 122 behind the machine (where it cannot be seen in FIG. 1),on a level with the bottom of the machine, and feeding the film fromthis roll through two right-angle turns around a triangular guide 230having a smooth outer surface. Thus the machine framework need not bedesigned to carry the roll in the usual position above the line ofpackages, and this provides important simplifications in construction.Overall construction also has been simplified by arranging the sealingdie so that evacuation takes place in the same position as does theperipheral heat sealing. By this means, atmospheric pressure duringevacuations provides a substantial amount of the force required to makethe seal, and thus the machine framework need not be designed to applythis force.

Referring again to FIG. 2, to the left of the package finishing station124 are mounted a second pair of discs 232 which are engaged by the tabs48 of the film clips 36 to open these clips for removal of the completedpackages. Adjacent these discs are respective curved guides 234positioned to engage the marginal side edges of the released packages,and arranged to cam these edges upward and out from between the fingers38 and 40 of each opened clip in succession. Thereafter, the completedpackage rides down the far side of the guides 234 and lands on the chute130, on which it exits from the machine.

Although a specific preferred embodiment of the present invention hasbeen described hereinabove in detail, it is to be understood that thisis merely to illustrate the invention and is not to be construed in alimiting sense, for it is clear that numerous modifications within thescope of the invention will be apparent to those skilled in this art.

What is claimed is:

1. Packaging apparatus comprising a plurality of elements arranged forintermittent indexing movement around a closed path, said elementsincluding means to grip and support the opposite side edges of a seriesof cups so that the cups are suspended in position to be operated on tomake packages, said cups having marginal portions around the open mouthsthereof with an evacuation opening in the marginal portion for each cup,each of said cups being provided over the mouth thereof with packagingmaterial adapted to form a top for closing the cup; a package finishingstation adjacent one index position on said path and including a diedefining a cavity shaped to receive said cups, a clamp operable withsaid die, said die and said clamp having seal means to engage saidmarginal portions of each cup, said seal means being arranged along aline extending around the entire periphery of the mouth of the cup atsaid one position and operable to efiect a permanent seal of said cup toits corresponding top at all points along said line to form an enclosedpackage; said seal means being located outboard of the evacuationopening of the cup at said one position so that the evacuation openingis located interiorly of said permanent seal line around the cup month;said finishing means further including vacuum means adjacent theevacuation opening of the cup at said one position and operable towithdraw air from the sealed package before it is moved to anotherposition; and close-off means adjacent said vacuum means, said close-elfmeans being operable after the evacuation of said package to permanentlyseal together the cup and its top around said evacuation opening beforethe package has been moved to the next position, thereby to provide bothevacuation and complete hermetic sealing of the evacuated package at asingle position.

2. Apparatus as claimed in claim 1, wherein said elements comprise aplurality of clips arranged to grip a web of packaging film at the sidesthereof; a forming station adjacent said path to form said web ofmaterial into said series of cups to be carried by said clips around tosaid finishing station; mean adjacent said path to make said evacuationopening in the marginal portions around each cup; means to apply saidpackaging material over the mouths of said cups to form said tops; andmeans to permit adjustment of said forming station longitudinally toaccommodate changes in the package length.

3. Apparatus as claimed in claim 2, including a support base for saiddie, said base being mounted for reciprocating motion towards and awayfrom the cups held by said clips; said vacuum means forming part of saidbase and including means extending up into the interior of said cavity;fastening means securing said die to said base, said fastening meansbeing readily disengageable to permit the die to be removed and replacedwith one of another size.

4. Packaging apparatus comprising a plurality of elements adapted togrip the side edges of a first continuous web of packaging material,said elements being arranged for intermittent indexing movement around aclosed path; a forming station adjacent said path for forming said firstweb into a series of cups each having a margin around the open mouththereof; means for making an evacuation slit through the trailing marginin each cup; means to apply a second web of packaging material over themouths of said cups; package finishing means adjacent said path at onecup position subsequent to said web applying means; said packagefinishing means comprising seal means arranged to engage said two Websalong a line extending completely around the mouth of the particular cupat said one cup position to form a package; said seal line passing overthe leading margin of the next following cup, said seal means at saidleading margin forming a permanent seal between said two webs, said sealmeans at the remaining sections of said seal line providing a permanentseal between said two webs at least in all parts of said line notalready permanently sealed; vacuum means adjacent the evacuation slit ofthe cup being sealed at said one position; said vacuum means beingoperable to evacuate the package through said evacuation slit before thepackage is moved to the next position; close-off means adjacent saidvacuum means and operable after evacuation of said package to seal saidtwo webs together around said slit before the package is moved to thenext position, so as to complete the hermetic sealing of the package;and means forming part of said finishing means for sealing together thetrailing margin of the next preceding cup while said means isoperatively engaged With said particular cup to be sealed, thereby tomake a seal line sealing otf the evacuation slit of that next precedingcup. 1

5. Apparatus as claimed in claim 4, wherein said seal means comprises areciprocable die formed of wall means each having planar end surfacesserving as sealing elements, said wall means further being arranged todefine a cavity to receive the cups after they arrive at said oneposition; said wall means including first and second walls extendingalong the outer side margins of each cup at said one position; a thirdwall extending transversely along the leading margin of the cup at saidone position, and a fourth wall extending transversely along the leadingmargin of the following cup at the next position behind said oneposition.

6. Apparatus as claimed in claim 5, wherein said die includes a fifthsealing element located a small distance ahead of said third wall andarranged to effect a seal on the trailing margin of the precedingalready-formed package in the position ahead of said one position.

7. Apparatus as claimed in claim 6, including knife means between saidthird and fifth sealing elements arranged to cut the package materialtransversely to separate the sealed packages into indiivdual units.

8. Packaging apparatus comprising a plurality of elements arranged forintermittent indexing motion around a closed path to carry a series ofcups having margins around the mouths thereof and with an evacuationopening in the margin for each cup, means to apply packaging materialover each cup to form a top therefor; a package finishing stationadjacent one cup position on said path, said finishing stationcomprising first and second heat seal means both engageable with themargins of a cup at said one position; said first heat seal meansextending at least substantially around the mouth of a cup at said oneposition and arranged to make a permanent seal between said cup and saidpackaging material completely around the mouth of the cup at said oneposition; said second heat seal means being located interiorly of saidfirst heat seal means, said second heat seal means being movable towardsand away from the margin of a cup at said one position and arranged toheat seal said packaging material to said margin completely around saidevacuation opening.

9. Apparatus as claimed in claim 8, wherein said first seal meanscomprises a reciprocable die and a cooperating heated clamp, said diehaving wall means defining a cavity arranged to receive said cup at saidone position, said wall means having planar end surfaces serving as sealelements to engage the margins around said cups, said second seal meansincluding a member mounted for reciprocating motion within the cavitydefined by said wall means and operable to press the packaging materialadjacent the evacuation opening against the heated clamp to complete theseal around that opening.

10. Packaging apparatus comprising a plurality of elements arranged forintermittent indexing movement around a closed path to carry a series ofcups having marginal portions around their mouths for sealing the cupsto respective tops; means for applying packaging material over said cupmouths to form said tops; a package finishing station comprising a clampmember arranged to engage marginal portions of a cup stopped at thatstation; a die member including wall means defining a cavity shaped toreceive the cup at that station, said die and clamp members having matedsealing elements for establishing a hermetically sealed chamber holdingsaid cup and its top with said sealing elements gripping said marginalportions; means for effecting relative movement between said die andclamp members to permit operations to be carried out on successive cups;heating means in said clamp member to heat the sealing elements thereofto effect a permanent heat seal at said marginal portions; vacuum meansto evacuate said chamber and to withdraw air from the package containedtherein through an evacuation opening in a part of the marginal portionsof the respective cup; and close-01f means reciprocable within said diemember for pressing said marginal portion part of each cup against saidheated clamp member to seal off the evacuation opening.

11. Apparatus as claimed in claim 10, wherein said elements compriseclip means arranged to grip the sides of a web of plastic film formedinto said series of cups, thereby to hold the cups suspended in positionto have packaging operations performed thereon.

12. Packaging apparatus comprising clip means arranged for indexingmovement around two parallel closed paths, said clip means being adaptedto grip the side edges of a series of cups and to support said cupssuspended from said side edges to permit packaging operations to beperformed thereon; means to apply packaging material to said cups toform tops thereof; a sealing die adjacent the line of movement of saidcups and including wall means arranged to receive said cups; meansmounting said sealing die for movement towards and away from said lineof movement to engage said cups in succession; a sealing clamp on theside of said cups opposite to said sealing die and including sealingsurfaces mating with corresponding surfaces of said sealing die to gripmarginal portions around the mouth of a cup in the sealing die and toform an air-tight compartment around that cup; said clamp having asection inboard of said sealing surfaces which is recessed relative tosaid sealing surfaces to be normally out of contact with said packagingmaterial; means for heating said clamp sealing surface and said recessedsection; vacuum means to evacuate the air from the cup through anevacuation opening in one part of a marginal portion thereof inboard ofsaid sealing surfaces; and a reciprocable pressure bar located withinsaid sealing die and arranged to move against said marginal portion partto press it tightly together with the adjoining packaging materialagainst said heated recessed section to heat-seal together the materialaround the evacuation opening.

13. Apparatus as claimed in claim 12, wherein said pressure bar islocated between the sides of said sealing die.

14. Packaging apparatus comprising a large number of clips arranged togrip the side edges of a first web of packaging material and to provideintermittent motion of that web around a closed path having lower andupper reaches; means to feed said first web of packaging material tosaid clips at a position thereof on said lower reaches; a vacuum formingstation on said lower reaches to form said web into a series of cupsbefore said web arrives at said upper reaches, said vacuum formingstation comprising a die mounted above said lower reaches and operableto form said cups with the mouths thereof facing downwardly; means atsaid upper reaches for applying a second web of packaging material overthe upwardly facing mouths of said cups; a package finishing station atsaid upper reaches including means to seal the two webs of materialtogether, said finishing station fur ther including means to evacuatethe package formed by said sealed webs; said clips being carried bychains and positioned with respect to the corresponding chain centerlineso that there is essentially no change in the gap between adjacent clipsas they move around the curved portions of the path of movement, therebyto eliminate tearing or distortion of said firstweb as it is moved fromsaid lower to said upper reaches.

15. Packaging apparatus comprising a large number of clips arranged togrip the side edges of a first web of packaging material and to provideintermittent motion of that web around a closed path having lower andupper reaches; means to feed said first web of packaging material tosaid clips at a position thereof on said lower reaches; a vacuum formingstation on said lower reaches to form said web into a series of cupsbefore said web arrives at said upper reaches, said vacuum formingstation comprising a die mounted above said lower reaches and operableto form said cups with the mouths thereof facing downwardly; means atsaid upper reaches for applying a second web of packaging material overthe up- Wardly facing mouths of said cups; a package finishing stationat said upper reaches including means to seal the two webs of materialtogether, said finishing station further including means to evacuate thepackage formed by said sealed webs; and means supporting said vacuumforming die in different positions providing difierent longitudinaldistances between said die and the package finishing station, thereby toaccommodate a change in the longitudinal dimension of the package.

16. Packaging apparatus comprising a pair of side-byside chains mountedfor movement around a closed path having upper and lower reaches; aplurality of spaced clips mounted on said chain and facing inwardly togrip the side edges of a web of packaging material to carry that webaround at least part of said closed path including a curved sectionthereof extending between said upper and lower reaches; a series ofstations adjacent said path at both said upper and lower reaches, saidstations including means for operating on said web of material to formpackages therefrom; said clips being positioned with respect to thecorresponding chain centerline so that there is essentially no change inthe gap between adjacent clips as they move around said curved sectionof said path, thereby to eliminate tearing or distortion of said web asit moves around said path.

17. Packaging apparatus comprising a pair of side-byside chains mountedfor movement around a closed path having upper and lower reaches; aplurality of spaced clips mounted on said chains and facing inwardly togrip the side edges of a web of packaging material to carry that webaround at least part of said closed path; a series of stations adjacentsaid path including means for operating on said web of material to formpackages therefrom; each of said clips comprising first and secondcooperating fingers for gripping the web there'between; said firstfinger being fixedly secured to the corresponding chain; both of saidfingers being formed with circular sections intermediate the endsthereof, said circular sections being in engagement to define a pivotaxis extending parallel to the chain axis and accommodating rotarymovement of said second finger with respect to said first finger; andspring means applying a force to said second finger urging it to rotateabout said pivot axis in a direction to effect engagement between theoutboard tips of said fingers, thereby to grip the web between saidtips.

18. Apparatus as claimed in claim 17, wherein said second finger isformed with a tab portion located between its pivot axis and thecorresponding chain; and cam means arranged to engage said tab portionto rotate said second finger about its pivot axis to spread said tipsapart and permit insertion of the web of packaging material.

19. Apparatus as claimed in claim 17, wherein said spring means includesmeans to secure said second finger to said first finger.

20. Packaging apparatus comprising a plurality of elements arranged tohold a first continuous web of packaging material for intermittentindexing movement around a closed path, said web being formed into aseries of cups each having margins around the open mouth thereof; meansfor making an evacuation slit through one margin of each cup; means toapply a second web of packaging material over the mouths of said cups;package finishing means adjacent said path at one cup positionsubsequent to said web applying means, said package finishing meanscomprising first seal means arranged to engage said two webs along aline extending completely around the mouth of the particular cup at saidone cup position and including a section passing along the adjacentmargin of another cup next in sequence, said seal means at said adjacentmargin forming a permanent seal between said two webs, said seal meansat the remaining sections of said seal line providing a permanent sealbetween said two webs at least in all parts of said line not alreadypermanently sealed; vacuum means adjacent the evacuation slit of the cupbeing sealed at said one position and operable to evacuate the packagethrough said evacuation slit before the package is moved to the nextposition; close-off means operable after evacuation of said package toseal said two webs together around said slit before the package is movedto the next position, so as to complete the hermetic sealing of thepackage; and second seal means operable subsequent to said first sealmeans for making a perment seal at said one margin of each cupinteriorly of said evacuation slit to seal said slit from communicationwith the interior of the cup.

21. Apparatus as claimed in claim 20; wherein said second seal means isintegrally mounted to said first seal means and is operative to makesaid permanent seal on a cup in the position next following said oneposition.

22. The method of making sealed packages from a continuous web ofpackaging material comprising the steps of advancing the web; formingthe web into a sequential series of cups having a predetermined repeatspacing along the longitudinal axis of the web and with marginalportions around the mouth of each cup; applying a second web ofpackaging material over the mouths of said cups to provide topstherefor; sealing said second web to marginal portions at each cup insequence, the seal line extending completely around the mouth of one cupand having a section thereof passing along a marginal portion of anadjacent cup so as to leave one marginal portion of said one cupunsealed; evacuating the. package thus formed through an opening betweensaid seal line section and said unsealed one marginal portion; closingoff said evacuation opening by sealing the two webs together in theregion of said opening; advancing the evacuated package to a subsequentstation; and sealing said two webs together along said one marginalportion of said cup to make a complete closed seal line passing over allof the marginal portions of said one cup.

23. Packaging apparatus comprising means arranged for motion around aclosed path to carry a series of cups having marginal portions aroundthe mouths thereof; means to apply packaging material over said cupmouths to make complete packages; a package finishing station adjacentsaid path and including a sealing die defining a cavity to receive andsurround each cup in succession; a sealing head cooperable with saidsealing die to heat seal said packaging material to the cup and effect apermanent outer seal line extending completely around the mouth of thecup; evacuation means at said finish ing station to evacuate the packagewhile still in said sealing die to effect said heat seal, the evacuationtaking place through an evacuation opening located interiorly of saidpermanent seal line; and close-01f sealing means at said finishingstation and operable while the cup is still in said sealing die toeffect a permanent seal between the cup and said packaging materialaround the. evacuation opening after the evacuation has been completed;the combination of the means for etfecting the outer seal line,evacuation, and close-off seal at the single finishing station making itreadily possible to accommodate a change package size by replacing thesealing die with a different die suited to the changed package size.

24. Packaging apparatus comprising a plurality of elements arranged forintermittent indexing movement about a closed path to carry a continuousweb of packaging material formed into a series of cups having marginalportions around the mouths thereof; means to apply a second web ofpackaging material over each cup to form a top therefor; a packagefinishing station adjacent one cup position on said path, said finishingstation comprising means for heat sealing said two webs together to forma permanent seal line extending completely around the mouth of a cup atsaid one position; said heat seal means comprising a sealing diedefining a cavity shaped to receive the cups and having sealing elementsto engage the web of packaging material around each cup; evacuationmeans to withdraw air from the interior of each cup through a slit inone marginal position thereof; and a stud fixedly mounted within saidcavity adjacent one wall of said die and directly beneath the part ofsaid one marginal portion which is outboard of said slit, the top ofsaid stud being aligned with the under surface of said one marginalportion so as to tend to hold the packaging material on one side of saidslit in position during evacuation of the cup.

25. Apparatus as claimed in claim 24, including a heated part above saidsecond web of packaging material in the region of said evacuation slit,and pressure bar means mounted for reciprocating motion along side ofsaid fixed stud to engage the under surface of said one margi nalportion and press it up against said heated part to close off saidevacuation slit after evacuation has been completed.

26. Apparatus as claimed in claim 25, wherein said stud is formed withan internal bore to permit the introduction of gas into the finishedpackage after evacuation thereof.

27. Apparatus as claimed in claim 24, wherein said finishing stationincludes a base member mounted for reciprocating movement towards andaway from the two webs of packaging material, means mounting saidsealing die to said base for ready removal therefrom to permitreplacement by a sealing die of different dimensions; said stud beingfixedly secured to said base member for operation with any sealing diesecured thereto.

28. Packaging apparatus comprising a plurality of elements arranged forintermittent indexing around a closed path to carry a series of cupshaving margins around the mouths thereof, means to apply packagingmaterial over each cup to form a top therefor; a package finishingstation adjacent one cup position on said path, said finishing stationcomprising heat seal means for making a permanent seal between said cupsand said packaging material along a line extending completely around themouth of a cup at said one position; said heat seal means having aportion thereof disposed to engage the margin of a cup at the nextposition beyond said one position so as to overlie part of the heat sealline previously produced by said heat seal means when the cup was insaid one position.

29. Apparatus as claimed in claim 28, including second heat seal meanslocated interiorly of the first heat seal means and movable relativethereto to heat seal an interior marginal portion of a cup in said oneposition to provide for closing off an evacuation opening therein.

30. Apparatus as claimed in claim 29, including third heat seal meansintegral with said first heat seal means and located exteriorly thereof,said third heat seal means being arranged to engage the cup at said nextposition so as to form a heat seal line overlying the close-ofi sealproduced by said second heat seal means.

31. Apparatus as claimed in claim 30, wherein said third heat seal meansis positioned to form a seal line running alongside said part of thepreviously produced heat seal line, whereby an evacuation openingtherebetween can be isolated from the interior of a cup at said nextposition.

32. Packaging apparatus comprising means arranged for motion around aclosed path to carry a series of cups having marginal portions aroundthe mouths thereof; means to form evacuation openings in said marginalportions; means to apply packaging material over the cup mouths and saidmarginal portions to make complete packages; a package finishing stationadjacent said path and including a sealing die defining at least onecavity reciprocably operable to surround each cup; a sealing headco-operable with the sealing die to establish a closed evacuationchamber within which an enclosed package is to be evacuated andhermetically sealed, said head and said die including interengageablemeans providing a gastight seal along an outer seal line extendingcompletely around the mouth of a cup within the die and at leastapproximately coplanar therewith; evacuation means at said finishingstation to evacuate the package while still in the sealing die, saidevacuation means being positioned interiorly of said outer seal line andincluding means to evacuate the package through the evacuation openingin said marginal cup portion of a cup in said sealing die; and heatingmeans at the finishing station operable, While the cup remains enclosedin the chamber formed by the sealing head and the sealing die, to effecta permanent heat seal between the cup and packaging material entirelyaround the cup mouth, said heating means including means operable toform a permanent heat-seal interiorly of the evacuation opening afterthe evacuation has been completed so as to prevent leakage of atmosphereinto the package interior.

33. Packaging appears as claimed in claim 33, wherein said evacuationmeans comprises means interiorly of said outer seal line to establish avacuum channel passing through said sealing die and communicating withan evacuation opening in said marginal portion outboard of the cupmouth.

34. Packaging apparatus as claimed in claim 33, including means operableto cut said evacuation opening in said marginal portion.

35. Packaging apparatus as claimed in claim 33, wherein said outer sealline is at least approximately rectangular in plan view, said evacuationopening being located adjacent one of the sides of the rectangle, saidsealing means including means operable to form a permanent heat sealalong a line parallel to said one side of the rectangle and at leastpartially interiorly of the evacuation opening.

36. Packaging apparatus as claimed in claim 33, wherein said sealing dieincludes flange portions surrounding said cavity and arranged to receivesaid marginal portions, said sealing head and sealing die being mountedfor relative reciprocating motion, said sealing head including meansengageable with said flange portions to establish said outer seal line.

37. Packaging apparatus as claimed in claim 36, wherein said sealinghead has mounted therein heated means interiorly of the means for makingsaid outer seal line and operable to form said permanent heat sealinteriorly of the evacuation opening.

38. Packaging apparatus comprising means arranged for motion around aclosed path to carry a first continuous sheet of plastic packagingmaterial through a series of stations where packaging operations areperformed along that path; first means adjacent said path to form saidfirst sheet into cups having marginal flange portions around the mouthsthereof; second means adjacent said path to cut the packaging materialof a flange portion adjacent each cup so as to make an evacuationopening through the flange; third means adjacent said path to apply asecond continuous sheet of packaging material over the cup mouths tomake complete packages; a package finishing station adjacent said pathand including a sealing die defining at least one cavity to receive andsurround each cup in succession; a sealing head co-operable with saidsealing die to establish a closed evacuation chamber, the engagement ofsaid head and said die providing a gas-tight seal along an outer sealline extending completely around the mouth of the cup and coplanartherewith; evacuation means at said finishing station to evacuate thepackage while it remains in the sealing die cavity, said evacuationmeans being positioned inboard of said outer seal line and adjacent thecut flange porttion of the cup so as to communicate with the evacuationopening and evacuate the package through the flange interiorly of theouter seal; and heating means at the finishing station operable, whilesaid cup remains in said die cavity and said evacuation means is incommunication with said evacuation opening, to effect a permanentheat-seal between the cup flanges and the overlying second sheet ofpackaging material entirely around the cup mouth, said heating meansincluding means arrranged to effect such permanent heat-seal in theregion between the evacuation opening and the package cup while thepackage remains in said die cavity, so as to prevent leakage into thepackage interior after the package has been removed from said sealingdie cavity.

39. Packaging apparatus as claimed in claim 38, wherein said sealing dieis reciprocably-operable into a closed position providing said sealingchamber within which packages are both evacuated and heat-sealed at onestop; and vacuum means for evacuating said sealed chamber, above andbelow the package, so as to provide reduced pressure both inside andoutside each package during the heatsealing thereof. 40. Packagingapparatus as claimed in claim 38, wherein said sealing head and sealingdie include aligned surfaces which establish said outer seal along aline extending entirely around the mouth of one package and additionallyencompassing at least a portion of the packaging material defining animmediately adjacent package, said evacuation means being positioned toevacuate said one package through an evacuation opening in the flangeportion between the two packages prior to heat-sealing the pack age tocut off communication between that evacuation opening and the evacuatedcup.

41. Packaging apparatus comprising means movable around a closed path tocarry a continuous sheet of plastic packaging material for packagingoperations at spaced positions along that path, said carrying meansincluding two sets of clips mounted for movement on parallel paths andhavmg opposed elements urged together to grip and support the side edgesof the sheet of plastic packaging material, the interior regions of saidsheet being formed into cups having marginal flange portions around theopen mouths thereof; means to apply a second sheet of packaging materialover the first sheet of packaging material to cover the cup mouths andmake complete packages; said sheet-gripping clips being arranged tocarry said first sheet with the second sheet positioned thereover into apackage finishing station where the packages are evacuated andcompletely sealed hermetically at a single stop; said finishing stationincluding a sealing die defining at least one cavity to receive andsurround each formed cup; a sealing head co-operable with said sealingdie to form a closed evacuation chamber, said head and said die providmga gas-tight seal along an outer seal line extending completely aroundthe cup, said outer seal line including sections running alongside theinboard ends of said clips immediately adjacent thereto; evacuationmeans at said finishing station to evacuate the package while it is inthe cavity of said sealing die, said evacuation means including meansdefining a passage extending up through a part of said sealing dieinteriorly of the said outer seal line and positioned to evacuate thepackage through an evacuation opening in a marginal flange portionadjacent the package cup being evacuated; and heating means at thefinish- 1ng station operable, while the cup remains in the cavity ofsaid sealing die for evacuation of the package, to elfect a permanentheat-seal between the first and second sheets of packaging materialextending entirely around the cup, said heating means including meansoperable after evacuation to effect such permanent heat-seal on an innerseal between said evacuation opening and the evacuated cup to preventleakage of atmosphere into the package interior after the package hasbeen removed from the sealing die cavity.

42. Packaging apparatus as claimed in claim 41, wherein said evacuationmeans includes means defining a vacuum passage located a substantialdistance inboard of the sides of said sealing die which are next to saidsheetgripping clips, said vacuum passage being positioned to communicatewith an evacuation opening in a marginal flange portion between saidouter seal line sections.

43. Packaging apparatus comprising a plurality of elements adapted togrip the side edges of a first continuous web of packaging material,said elements being arranged for movement around a closed path; meansfor moving said elements with an intermittent indexing motion providinga dwell period between indexing steps for carrying out packagingoperations; a forming station adjacent said 17 path for forming saidfirst web into cups having margins around the open mouths thereof; meansfor making an evacuation slit in the packaging material between pairs ofadjacent cups; means to apply a second web of packaging material overthe mouths of said cups and the margins thereof to form completepackages; a package finishing station adjacent said path at one positionsubse quent to said web applying means for evacuating and hermeticallysealing each package at a single stop; said package'finishing stationcomprising a reciprocably-cooperable sealing die and sealing head havingengageable seal means arranged to form an air-tight seal along an outerline extending completely around the mouth of one cup at said oneposition, said outer seal line encompassing the slitted margin adjacentsaid one cup and also encompassing at least a portion of the packagingmaterial of the next adjacent cup beyond said evacuation slit; vacuumconduit means within said die aligned with the marginal evacuation slitof the package in said die at said one position; said vacuum conduitmeans being operable during a single dwell period to evacuate thepackage through said evacuation slit; and heating means operable at thepackage finishing station during the evacuation dwell period forproducing a permanent heat seal between said two webs ofpackagingmaterial entirely around the mouth of said one cup in said sealing die,said heating means including means operable to seal said two webstogether between said evacuation slit and the mouth of said one cupbefore the package is moved to the next position, so as to evacuate andhermetically seal the package during a single dwell period of saidintermittent indexing motion. 44. Packaging apparatus of the typewherein package sealing and evacuation take place at a single station,said apparatus being adapted for convenient changing of packagedimensions and comprising:

a plurality of spring-loaded clips adapted to grip the side edges of afirst continuous web of packaging material, said clips being arrangedfor movement around a closed path;

means for moving said clips with an intermittent in-' dexing motionproviding a dwell period between indexing steps for carrying outpackaging operations;

a forming station adjacent said path for forming said first web intocups having margins around the open mouths thereof;

means for making an evacuation slit in a margin in the packagingmaterial between pairs of adjacent cups;

means to apply a second web of packaging material over the mouths ofsaid cups and the margins thereof to form complete packages;

a package finishing station adjacent said path at one positionsubsequent to said web applying means for evacuating and hermeticallysealing each package at a single stop;

said package finishing station comprising a reciprocable sealing diehaving a cavity to receive a cup;

a sealing head having means arranged to contact said die to form anair-tight seal between the two webs of packaging material along an outerseal line entirely encompassing the mouth of a cup in said die, saidouter seal line comprising portions extending alongside but interiorlyof said clips at the edge of the web of packaging material, said outerseal line also encompassing the slitted margin adjacent said one cupwhereby access to the interior of the package in the die can be hadthrough the slitted margin while the cup is sealed in the die;

heating means for maintaining the seal means at an elevated temperatureso that the engagement between the seal means and the packaging materialproduces along said outer seal line between the two webs a permanentseal which is hermetically effective after removal of the package fromthe die;

vacuum conduit means at said die, said vacuum conduit means beingaligned beneath the marginal evacuation slit of the package in said dieat said one position and operable during a single dwell period toevacuate the package through said evacuation slit; and

close-01f sealing means operable at the package finishing station at thecompletion of evacuation for producing a permanent heat seal betweensaid two webs of packaging material in a region between said evacuationslit and the mouth of said one cup before the package is removed fromthe die for transfer to the next position, thereby to evacuate andhermetically seal the package within a die which can readily be replacedwith a similar die of different size to form different-sized packages.

45. Apparatus as claimed in claim 44, wherein said close-off sealingmeans comprises a heated element in said sealing head; and

reciprocable means operable to effect compressive engagement between thepackaging material and said heated element while the package remains inthe die after evacuation thereof.

46. Apparatus as claimed in claim 44, wherein said closed path ofmovement of said clips is generally oval in configuration, as seen in anelevation view, and includes both lower reaches and upper reaches;

means adjacent said lower reaches for applying said first web ofpackaging material to clips at said lower reaches;

said forming station being located at said lower reaches and operable toform cups in an upside-down position, the movement of the clips servingto carry the first web with the formed cups around the oval path to theupper reaches whereby the cups are inverted to right-side-up position tobe loaded with product for packaging; and

said package finishing station being located at said upper reaches.

References Cited UNITED STATES PATENTS TRAVIS S. McGEHEE, PrimaryExaminer US. Cl. X.R.

